The objective of this research project is to produce and characterize monoclonal antibodies against the simian immunodeficiency virus (SIV). It has been documented in the literature that SIV infection of macaques provides an animal model remarkably similar to the acquired immunodeficiency syndrome (human AIDS). Techniques like Western blot, immunofluorescence and enzyme linked immunosorbent assay (ELISA) are currently used in AIDS research. Some of these techniques require the use of monoclonal antibodies for identification of antigen and antibodies. Monoclonal antibodies against human immunodeficiency virus type 1 (HIV-1) are commercially available and are currently used to detect viral protein expression in clinical and research protocols. However, this is not the case for SIV. This work is aimed at developing monoclonal antibodies against SIV for the detection of virus-specific antigens and proteins. The monoclonal antibodies will be produced according to Kohler and Milstein (Nature 256: 495-497, 1975). They will be concentrated by the ascitic fluid technique and purified by chromatography. Their specificity and cross-reactivity (against SIV and HIVs, respectively) will be tested by ELISA and Western blots. Their biological activity will be tested by immunofluorescence reverse transcriptase and syncytia inhibition assays.